Even in your archive? I remember your archive of Queen recordings as a place where is a lot of rare things... Maybe some extended version of Wembley'86 are there too ;)
Look at it like this...
He ANNOUNCED that he´s searching for a demo concert on the b-side of some 12" single!
In this case the ANNOUNCE section seems to be absolutely right!!! :-)
You want to check out allofmp3.com ...it has some excellent bootlegs, in great quality btw, and all the 12" mixes and B-Sides you can shake a stick at!! Best of luck to ya bud!!